Power take-off units are mechanical devices that are used in conjunction with sources of rotational energy, such as vehicle engines and transmissions, for selectively providing power to one or more rotatably driven accessories. For example, power take-off units are commonly used in a variety of industrial and agricultural vehicles for operating hydraulic pumps that, in turn, operate hydraulically driven accessories, such as plows, trash compactors, lifting mechanisms, winches, and the like. Power take-off units may also be used to connect the vehicle engines and transmission to an auxiliary device, such as a generator.